We present a relativistic and cross-section factorized framework for computing nuclear transparencies extracted from $A(\gamma ,\pi N)$ reactions at intermediate energies. The proposed quantum mechanical model adopts a relativistic extension to the multiple-scattering Glauber approximation to account for the final state interactions of the ejected nucleon and pion. The theoretical predictions are compared against the experimental ${}^4\mathrm{He}$$(\gamma ,p{\pi }^{-})$ data from the Thomas Jefferson National Accelerator Facility. For those data, our results show no conclusive evidence of the onset of mechanisms related to color transparency.

• Received 25 July 2006

DOI:https://doi.org/10.1103/PhysRevC.74.062201